System of electrical transmission and propulsion.



.PATENTED DEC. 24, 1907.

M. LEBLANG. v SYSTEM OF ELECTRICAL TRANSMISSION AND PROPULSION.

APPLICATION FILED MAR. 31, 1904.

3 SHEETS-SHEET 1.

PATENTED DEC. 24, 1907.

M. LBBLANO. SYSTEM OF ELECTRICAL TRANSMISSION AND PROPULSION.

APPLIGATION FILED MAR. 31, 1904.

3 SHEETSSHEET 2.

Suva doc; jm Z472 c No. 874,411. PATENTED DEC. 24, 1907.

M. LEBLANO.

SYSTEM OF ELECTRICAL TRANSMISSION AND PROPULSION.

APPLICATION FILED MAR.31,1904.

3 SHEETS-SHEET 3.

" UNITED STATES PATENT OFFICE.

MAURICE LEBLANO, OF PARIS, FRANCE, ASS IGNOR TO WESTINGHOUSE ELECTRIC &-MANUFAOTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

SYSTEM OF ELECTRICAL TRANSMISSION AND PROPULSION.

I To all whoin it may concern."

dent of Paris," France, have invented a new and useful System ofElectrical Transmission andPropulsion, of which the following is a secification, v

It as been proposed,' in Patent No. 527857, of October 23, 1894, toHutin &; Leblanc, to drive electric tram cars by extending along thetrack an insulated wire traversed by currents of high frequency and byroviding the car with a secondary circuit including a coil serving thepurpose of the secondary coil of a transformer, it being understood thatthe portion of the line wire which is in inductive proximity to thesecondary coil corres onds to the primar a transformer whi e thesecondary coi on the car corresponds to the secondary coil of thetransformer. There is, however, this difference over transformers asuniversally constructed, that in the latter a liminated iron core isprovided for interlinking the primary and secondary circuits, while inthe system referred to, since the secondary is continually shifting itsposition, no such iron core can be employed and the magy of the aternating current sufficiently high and thatthere Wlll be noconsiderable loss -with the production of netic circuit must be closedthrough the air. But the apparent self induction ofthe secondary 001having been approximated to zero for the frequency chosen, by any suit--able means, it Wlll be plain that any desired amount'of electricalenergy can be inductively'transferred from the line wireto the secondarcircuit by taking the frequency of energy by wasteful induction in thetrack rails and metallic bodies within inductive proximity-of the linewire, since such metalc bodies have not had their self inductionrendered zero for the given frequency and .hence offer a high impedanceto such high frequency currents.

- My present invention, which relates to means for carrying into effectthe system just outlined, is not concerned with the production of thehigh frequency currents which are to be employgd, that is to say rentsthe effective intensity. and frequency of which are sufficientlyconstant so that there may be utilized with them all the prop erties ofelectrical resonance. Nor does my Specification of Letters Patent.Application filed larch 31.1904. Serial No. 200.908.

gh frequency cur Yatented Dec. 24, 1907.

.present invention concern itself with the avoidance of the elevation ofthe ap arent resistance of the line wire due to the hom- .son effect,since this may be accomplished by building it of thin, lightlyinsulated, and twisted Wires or of thin tubes. My invention is, however,concerned with the trans mission of the high frequency alternatingcurrents over the line wire. In the transmission of alternating currentsof the frequency now commonly employed, the length of the electricaltransmission line is very short when compared to the length of theelectric wave whlch it carries. But with the frequencies which I employ,the length of the electric wave is short with relation to the length ofthe transmission line. In fact whether or not the frequency of thealternating current which I emplo is high is to be determined, in so faras t e present aspect of my invention is concerned, by the crite rionwhether or not the electric Wave corresponding to the given frequency isshort with respect to the transmission line empkg ed.

y the present aspect of my invention, I mean its as ect as regards thetransmission of energy a onga transmission line, as distinguished fromthe later use' of such currents for propelling vehicles. Now inv thecase of an electric transmission line carrying electrical waves of awave length which is short with respect to the length of the line, I maysay that such lines'ac't with reference to the electrical waves just assonorous tubes act with relation to sound waves. There will exist thetransmitted waves, the reflected waves and, in certain cases, standingwaves, with nodes and loops. What is more, the waves which propagatethemselves along the line will die down more rapidly when the line givesup energy at various points along its length, as happens when thetransmission line is used for a system of pro ulsion like thatheretofore outlined, than w en the line gives up energy at itsextremity, only, as in the transmission from a generator at one end to amotor at its other end. Finally the line may become the seat ofresonance phenomena which give rise to very objectionablesuper-elevations of voltage. 4

One of the objects of my invention is to prevent any objectionable suer-elevation of voltage in transmission of high frequency currents.Again, when my transmission line loo , elevation of voltage.

is used for electric propulsion, it is necessary to prevent theformation of standing nodes along the line, since at such nodes avehicle can draw no electrical energy from the line.

Another object of my invention is, then, the prevention of such nodes.

N ow to prevent the production of nodes in the transmission line, it ismanifestly sufiicient to prevent the formation of the re flecte d waves,that is to say the waves which are reflected from the end of the linedistant from the generator back to the generator. This becomes clearwhen we consider that the nodes accompany the standing waves which areroduced by the combination of the transmitted and the reflected waves.In order to prevent the reflection of the electrical waves from the endof the line distant from the generator, I provide the line with aterminal circuit of such resistance and inductance as will absorb allthe energy which is transmitted to it. But as this wouldresult in aconsiderable loss of energy, I furthermore have the circuit whichterminates the line do some useful work. For instance, by bending thetransmission line in the form of a loop, I maybring the terminal circuitback to the generator and I may thereupon restore the energy in theterminal circuit to the generator by any suitable transforming device.To avoid the super-elevation .of voltage along the transmission line, Iartificially increase the ratio ofits capacity to its inductance atnumerous points along the line, the consecutive distances between whichare short with reference to a half Wave length of the current. But inorder that the deadening of the waves may not be increased by thisincrease in the capacity or decrease in the apparent inductance of theline, I so arrange this artificial increase that the ratio of theinductance to the capacity Will grow greater and greater as thegenerator is receded from. Finally, in order to be able to use a directcurrent motor on my vehicle, I rectify the alternating currents of highfrequency, whichare developed in the secondary coil on this vehicle, bymeans of a system of electric valves which permit currents to pass in agiven direction but prevent the passage of current in the oppositedirection. All this will become more clear by reference to the drawingsin which Figure 1 shows my transmission line. Fig. 2 shows theelectrical waves thereon.- Figs. 3 and 4 show means for reventing thesuper- 'g. 5 is a side eleva: tion of my car-and transmission line. Fig.6 is a front elevation of the same. Figs. 7 and 8 are details of theelectric valves which I may employ. Fig. 9 is a diagram of the cir:cuits of the car. Fig. 10 is a diagram of a modification and Fig. 11 isa sectional elevation showing an underground conductor.

In Fig. 1 I have indicated by the letter S 1 an alternating currentgenerator of high frequency. It will be understood however, that mypresent invention has nothing to do with theparticular construction ofthis generator so long as it is an apparatus which generates alternatingcurrents of high and practically going wire 1 eads to one 'side of theterminal circuit F from the other side of which the return wire 2 leadsback to the generator. Designating by r, c and l the resistance, the

sion line assumed to be uniformly distributed in units of length and bythe frequency of the currents which it transmits, I have found that theterminal circuit should have a resistance R and a co-efficient ofapparent self induction L given bythe equations new mgr J2me ml Whenthese conditions are fulfilled, the tere minal circuit is of a characterto absorb all the electric wave energy which comes to it, so that thereis no reflected wave proceeding node. I v

As I have before intimated, instead of merely wasting the electricalenergy inthe sired manner. The particular mode of employing the energyin the terminal circuit F will most natura .be adapted to the char actorof the hi h rent generator In Fig. .2 I have indicated by-the'curve-Ithe values, ata given moment of'time, of the intensity of the currentalong the line and by the curve H the values of the voltage at the samemoment of time, at corresponding oints on the line. These two curveshave een shown dephased by about 90 degrees. Theam litudes of theiroscillations diminish gradual y as we get away from the source ofelectricity, this being due to ,the deadenln forces which are at work.It is to be noted that the electromotive-force of'thesource S, necessaryto maintain the current on. the line, depends on the deadening forcesopposed to the propagation of the current. But the maximum value of thevoltage at constant freiiuency and strength. The outcapacityand theinduction of the. transmisfrom the terminal circuit back to thegenerator, no standing wave and no stationary terminal circuit in theform of dissipated transmissionline in the form ofa loop, as Theterminal circuit F' cated later on and then utilized in any de-- equencyalternating cur- 'of which the line is the seat.

any given point along the line depends, on the other hand, primarilyupon the resonance I assume that I may neglect r. with respect to m land that the quantities 1', c, l, may'vary as onemoves along the line.The velocity v of propagation of the waves is equal to V and. their lawof deadening is such that if we designate by A, the effective intensityat a pointsituated at a distancea: from the source,

and by A, the effective intensity at a point situated at a distance 12:from thesource, the uantities r, c, -l,remaining constant between 't epoints x and m, then one has It can further be shown that the effectivevoltage at the point a: is equal to In orderto diminish the deadening ofthe waves, it is manifestly desirable to diminish the value-of thefraction 1 that is to say it is desirable either to diminish thecapacity of A the line or to increase its self induction,

that we increase the ratio of the self induc tion to the capacity, thevoltage which the;

line has tosupport is also increased. Now it so happens that in nearlyall practical cases, the natural value of the ratio of the capacity tothe self induction will be sufliciently small so that one may attain, ata reasonable cop-v per cost, a sufficiently great distance ofelectrical. transmission without an undue deadening of the intensity ofthe current waves along and at the end of the line. But, on the otherhand, in practical cases, withan unmodified transmission line, it willbe found that the super-elevation of voltage along the a line will besohigh as to render the insulation of the conductors difficult. I, Forthis reason, that is for the purpose of preventin the super-elevation ofvoltages along the hue, I. artificially decrease the ratio ofthe selfinduction to the capacity of the line, at points along the 'line, theconsecutive distances between which points areshort with reference to ahalf wave length ofthe current. Since we are dealing with the ratio ofthe-self induction to the capacity, that is with the fractionit ismanifest that we can change its value by varying either its enumeratoror its .wave length and, in this way, I have increased the capacity c ofthe line which means that I have decreased the ratio of the selfinduction to the capacity. This results in diminishing the voltage alongthe ine. In

Fig. ,4, on the other hand, I have shown condensers in series in the outoing line by which means I have, in effect, re uced the apparent selfinduction 1 of the line.

induction to the capacity of the line and with it the voltage which theline is compelled to support. But in order that the deadening of t ewaves may not become more and more rapid as we recede from the primesource of energy along the transmission line, it will be observed that Ihave decreased the size of the added condensers as we pass along theline away from the generator, toward the line terminal. This means thatthe ratio of the self induction to the capacity is gradually varied inan increasing manner along the line, as we get toward the line terminal,and this at points the consecutive distances between which are shortcompared with half a wave length of the current. I remark again thatthis radual variation in an increasing manner of the ratio of the selfinduction to the ca acity toward the line terminal may be brouglit abouteither by increasing the self This means that I have again decreased theratio of the self induction, apparent or real, or by diminishmissionline is made of diminishing cross section toward the line terminal sincethis part of the line carries a current of less effective intensity. 4

I have shown in Fig. 5, an-electrical tram car or automobile, thedistinguishing characteristic of which, so far as shown, is a largerectangular frame. This frame carries the secondary coil 3, beforedescribed, inductively receiving, on the one hand, electrical energyfrom the line wire 1,.which acts as a primary, and transmitting in turnthe elec trical energy thus received, in :a manner which will appearlater on, to the motor on the tram car.

In Fig. 6 the two line wires 1, which are supported upon posts, arecoupled in parallel, thus constituting, in effect, a single line wireand their return wires 2, also coupled in parallel, are embedded atthefoot'of the posts. The path of the magnetic flux, generated by the linewires 1, is shown by the dotted loop W and is seen to traverse thesecondary coil 3. The line wires 1 are insulated but the return wires 2need not be insulated.

In Fig. 11, I have shown a single line wire 1 resting on the top of aninsulator 1 1, which is covered by flag stones 112.

wires 2 are embedded near the rails 20 u on which the tram car travels.The secon ary 3 is' supported in any'convenient manner.

upon the vehicle in a plane which preferably passes through the linewire 1. In order that the line wire 1, in Fig. 11, may act mostefficiently as a. rimary,inductivelytransmitting electrica energy to thesecondary 3 on the tram car, it is manifestly necessary that it shouldbe located as shown, that is to say. it

l the line wire 1.

should lie in a vplane which passes through So long as t etram carremains u on the tracks 20, this condition will necessarily-befulfilled. But in the case of the automobiles shown in Fi s. 5 and 6,which do not travel upon trac it will be manifestly desirable to permitthese automobiles to depart from the inductive region of thetransmission line 1, asfor instance to avoid anobstruction or to turnout for another vehicle. In order to render this possible, I have addeda storage battery to the automobile equipment, which storage battery isarranged to be charged during the period when the automobile isreceiving energy from the line wires 1 and is arranged to feed the motoron the automobile at other times. The specific arran ement of thisstorage battery will be descri ed farther on. l have stated at theoutset of this specification, and it is fully described in Patent No.527,857 there referred to, that for the purpose of transmittingelectrical energy from a ne wire to a secondary. coil'without theintervention of an iron core, it is necessary for economy to use highfrequency currents. Only when such high frequency currents are employedwill the dissipation losses in extraneous conductors be small. Underthis aspect of my invention usethe term hi h frequency as meaning a freuency su clently high to avoid undue dissipation of the current energyin extraneous conductors. But when such. high frequency currents areemployed upon the line wire, 1t follows that big frequency currents willbe generated in the secondary clrcuit 3 and, unless these currents arethen transformed, the hi h frequency currents will be supplied to t emotor. It happens, however, that there is, at the present day, no knownform of motor which is capable of efficiently utiligin high frequencycurrents. For this reason have employed the arrangements of circuitsdiarammatically indicated in Fig. 9, whereby I rst approximate to zero,for the employed frequency, the coefficient of apparent self induction.of the secondary coil 3 by a suitable condenser and thereupon transformthis alternating hi h frequenc current into a direct'current by means ofelectric valves. In this manner I am permitted to use any known form ofdirect current motor to drive the ve- The return.

hicle. The use of electric valves in this connection forms a peculiarlyuseful means for utilizing upon a vehicle the energy of high fre uencycurrents upon a, line wire and I regar this as an important feature ofmyinvention.

Examining Fig.9, we find that the secondary coil 3 is in circuit with acondenser 4, the

given frequency of the alternatin current, the co-efiicient of apparentself induction of the cricuit including the coil 3 will be rendered zeroor as nearly zero as ma be desirable for commercial purposes. denser isshunted by a spark gap 41 which revents the puncturing of the condenser.I fhrther include, in the cirtzuit of the secondary coil 3, the primary5 of a transformer 50 and I may finally include in this circuit the twocoils 6 and 7, series with each other and which are movable with respectto each other, for the purpose of. varying the, co-efficient of apparentself induction of the circuit 3, 4, 5, 6, 7, in which they findthemselves. The coils 6, 7, constitute one type of variable reactancewhich I may employ.

The transformer 50 has two secondary coils 8 and 9 each of the samenumber of turns but oppositely wound. These are connected, at one end,to the binding post 10. Connected to the other end of the coil 8 is acoil .11 and connected to the other end of the coil 9 is a coil 12.These two coils 11 and 12 also each have the same number'of turns butare oppositely wound. The other terminals of the coils 11 and 12 arerespectively connected tothe terminals 0,, a, of like sign, of anelectric valve 15. Coperatcapacity of which is so chosen that for the heconing with these two terminals a and a, of

binding posts 16 and 10-and the motor M,

which drlves the vehicle, and its rheostat M are connected up in shuntof the secondary battery. Briefly describing these electric valves, twot pes of which have been shown in Figs. 7 amI S, I may constructed in avariety of ways. instance, they may consist of a vacuum tube containingtwo opposite electrodes which are say that the may be p 1 Thus, for

dissimilar either in the nature of the sub- 7 stances which compose themor in their geo metric form. By way of example, the positive electrode pma be made pointed and the ne ative electro e 12. may be made globular.This has been shown in Fig. 7. r the negative electrode may consist of alobule of mercury'and the positive electro e may be made of a bell ofsteel. 1 This unusually efficient form of electric valve is shown inFig. 8. In any case, if an alternating current is 1mpressed upon theterminals 'of'the electric valve, current in one direction is allowed toflow and the current in the oppositedri motion is, in effect,suppressed. It will now in circuit therewith, will induce into thesecondary coil 8 of the transformer 50 our-- rentin such a direction aswill enable it to flow across the valve terminals t e. in the next halfperiod of current, on the ot ier hand, the current which is induced inthe secondary 8 by the rimary 5, being in a direction opposite to t atjust referred to, will not be permitted to flow. But during this halfperiod, the current which the primary. 5 induces in the secondary 9 ofthe transformer 50, may freely pass from the valve terminal I) to thevalve terminal a It thus happens that each half wave of ourbattery.

It is manifest that the successive passage of currents in the samedirection in the secondary coils 8 and 9 will roduce the same effectupon the primary coil 5 as the passage of an alternating current ineither one of the coils 8or 9. The same remark applies to the coils 11and 12 with relation. to the coil 13. It is therefore manifest thatmatters will proceed so far as the mutual inductionof these coils isconcerned precisely as if the were but asingle circuit 8, 11, carryingan a ternating current instead of there being, as is actually the case,two parallel circuits 8, 11,

andg, 12, each carrying successfully one half wave of the alternatingcurrent.

By choosin the capacity of the condenser 14 in circuit with the coil 13in such a manner that the co-efficient of apparent self induction of thecircuit formed by the union of the coils 8, 11, is zero, it will beapparent, from what is known of transformer action, that the voltage orelectrical pressure developed between the binding posts 10, 16, isproportionalto the strength or intensity of the currentin the circuitcontaining the coils 3 and 5. In order to control the voltage across theterminals 10 and 16, it is therefore merely necessary to control theintensity of the current in circuit 3, 4, 5, 6, 7, and this ma be"readily done by varying the co-efl'icient 0 self induction or thereactance of this circuit by moving the coil 6 with reference to thecoil 7.

As has been previously pointed *out, the secondary battery 160 ispeculiarly necessary in case of automobiles whiclrmay be com pelled toleave the region of inductive effect of the line wire 1, as or instance,in turning out for another vehicle. It is necessary, however, whenemploying a secondary battery, to have an approximately constantdifference of potential between its terminal binding posts. Since,however, the co-effi.

D ur- I minishing the self induction.

cient of mutual induction between the seccient of self induction or thereactance of the circuit 3, 4, 5, 6, 7, be suitably varied, as forinstance by manually manipulating the coils 6, 7, with relation to eachother. It is also evident that as the vehicle approaches the terminalcircuit, where its secondary coil 3 will be sub'ected to the inductiveaction of currents of less intensity, that the co-efiicient of selfinduction of the circuit 3, 4, 5, 6, 7, should be decreased. The speedof the mo tor may be controlled by any type of rheostat M.

In case we are dealing with tram cars which run along tracks and whichwill therefore always be within the inductive influence of the line wire1, the storage battery will be dispensed with and the motor will beinserted directly between the terminals 16 and was shown in Fig. 10. Inthis case the speed of the motor Wlll be changed by varying the re .foradding capacity to a line either for the purpose of increasing thecapacity or of di- But it is now well understood in the art that 'anumber of other types of apparatus have this same property and I shallspeak of all such types of apparatus under the generic title of acapacitance or capacitances.

1. An electrical transmission line, can "ng alternating currents of awave length w ch is short with reference to the length of the line,which has the ratio of its capacity to its self induction artificiallyincreased at points along the line in a manner to prevent the suerelevation of voltage, the consecutive istances between which pointsare short with reference to a half wave length of the current,substantially as described.

2. An electrical transmission line, 0 'ng alternating currents of awavelength w 'eh is short Wlth reference to the length of the line,which has the ratio of its selfinduction to its capacity graduallyvaried in an increasing manner toward the, line terminal, at pointsalong the line the consecutive distances between which are short withrefer ence to a half wave length of the current, substantially asdescribed.

3. An electrical transmission line, carryi alternating currents of awave length whic is short with reference to the length of the line, andcapacitances added at points along the line to artificiall increase theratio of its capacity to its sel induction in a manner to prevent thesuperelevation' of voltage, the consecutive distance between thecapacitances being short with reference to a half wave length of thecurrent, substantially as described. Y

4. An electrical transmission line carr ing alternati currents of a Wavelength w 'ch is short w1th reference to the length of the line, andcapacitances of gradually diminishing capacity at points along-theline'to artificially increase the ratio of its capacity to its selfinduction, and to gradually vary the ratio of its self induction to itscapacity in an increasing manner toward the line terminal,

- .scri ed.

Y pressing thereon alternating currents of a the consecutive distancesbetween which oints are short with reference to a half wave en th of thecurrent, substantially as de- 5. Anelectrical transmission line, m 'ngalternati currents of a wave length w ich is short with reference to thelength of the line, comprising a terminal circuit of a character toabsorb the electrical energy trans-.

mitted toit, whereby reflectedv waves are.

avoided, substantially as described.

'6. Anelectrical transmission line, carryi alternati currents of a wavelength which isshort w1th reference to the length of the line,comprising a terminal circuit having a resistance and a co-efficient ofa arent self induction determined to avo1 reflected waves, substantial]as described.

7. The combination of anelectrical transmission line, and an electricalgenerator imwave length which is short with reference to the lengt ofthe line, the transmission line comprlslng a terminal circuit, injuxtaposition'to the generator, of a character to absorb the electricalenergy transmitted toit, whereby reflected waves are avoided and thesubstantially as describe 8. In a system of electric propulsion, a linewire carrying high frequency currents, and a vehicle carrying anelectric'circuit in inductive proximity thereto which has itsco-efficient of self induction approximated to zero I for the givenfrequenc an electric valve for rectifying the induce alternati currents,and a. motor for driving the vehic e actuated by the'i rectifiedcurrents, substantially as de 8011 e 9. In a system of electricpropulsion, a line wire carry ng high frequency currents, and a vehicle0 the rectified currents,

absorbed electrical energy may be utilized the vehicle actuated byenergy, which consists inductive proximity thereto, which has itsco-efficient of self induction approximated to zero for the givenfrequency and which in cludes a variable reactance, an electric valve ina circuit which is inductively related to that last'specified forrectifying the currents,

and a stora e battery char ed b the rectified scribed. I

12. In a system of electric propulsion, a linewire carry ng highfrequency currents,

and a vehicle carrying an electric circuit, in

inductive proximity thereto, which has its co-efficient of selfinduction approximated to zero for the given frequency, an electricvalve in a circuit of approximately zero apparent self induction whichis inductively reated to that last specified for rectifyin the currents,and a motor for driving the ve 'cle actuated by the rectified currents,substan tially as described.

'13. In a-system of electric propulsion, a line wire carrying high freuency currents, and aivehicle carrying an, e ectric circuit, ininductiveproximity thereto, which has its co-efiicient of apparent selfinduction approximated to zero for the given frequency and whichincludes a variable reactance, an electric valve in a circuit of aproximately zero apparent self induction wl iich is inductively relatedto that last specified for rectifying the current, and a motor fordriving the rectified currents, substantially as described.

14. The process of transmitting electrical in impressing upon atransmission line high frequency alternatin currents of a wave lengthwhich is short wit reference to the length of the line, andcounteracting the tendency to elevation of voltage t e by artificiallyincreasing the ratio of capacity to the self induction atpoints along II the hne, the consecutive'distances between which are short withreference to a half wave length of the current, substantially asdescribed.

15. The process, of transmitting electrical energy, which consists inimpressing upon a transmission line alternatin currents of a wave lengthwhich isshort with reference to the length of the line, andcounteractin' the tendency to an increasing deadening 0 the waves towardthe line terminal by gradually varying in an increasing manner,toward-the line terminal, the ratio of its self induction to its caacity and this at oints the consecutive distances between w 'ch areshort with reference to *a half wave length of the current,substantially as described. 1

16. The process of transmitting electrical energy, which consists inimpressing, upon oneend of a transmission line, alternating currents ofa wave length which is short withreference to the length of the line,and absorbing the electrical energy transmitted to the other end of theline, for the purpose of avoiding reflected Waves, substantl ally as described.

17. The process of transmitting electrical energy, which consists inimpressing by means of an electrical generator upon one end of atransmission line, alternating currents of a wave length which is shortwith reference to the length of the line, absorbing the electricalenergy which is transmitted to the other end of the line, and utilizingthe energy thus absorbed, substantially as described. r

18. The process of transmitting electrical energy which consists inimpressing upon a transmission line alternating currents of a wavelength which is short with reference to the length of the line, andcounteracting the tendency to an elevation of voltage and to theincreasing deadening of the waves toward the line terminal, byartificially increasing the ratio of the capacity to the self inductionat points along the line, the con secutive distances between which areshort with reference to a half wave length of the current, and bygradually varying in an increasing manner the ratio of the selfinduction to the capacity at these points as the line terminal isapproached, substantially as described.

. In testimony whereof I have signed my name to this specification inthe presence of two subscribing witnesses.

MAURICE LEBLANC.

Witnesses:

ALBERT DELAS, HANSON (J. OoXE.

